The invention relates to a blading for a turbomachine, in particular an internal combustion engine having at least one compressor stage, combustion chamber and turbine stage, preferably a gas turbine, according to the preamble of claim 1, and a manufacturing method for such a blading.
A blade passage of a turbomachine is generally defined by a hub-side and a housing-side lateral wall as well as guide vanes or rotating blades disposed therebetween, each of the lateral walls being able to be fixed relative to the hub or housing. Increased deflections of the flow may occur in blade passages due to the effect of wall friction in the region of the lateral walls, whereby in part strongly pronounced secondary flows result. These secondary flows cause increased losses.
A blading for a turbine is known from EP 1 995 410 A1, in which thickened areas are formed at suction and pressure sides as well as behind the trailing edges of the blade and depressions are formed in the center between adjacent blades on a lateral wall having a plurality of blades. Bladings for turbines or turbomachines are known from EP 2 248 966 A1 and DE 32 02 855 C1, in which elevations are formed on a lateral wall having a plurality of blades.
The object of the present invention is to provide an improved blading and a method for the manufacture thereof.
This object is achieved by a blading with the features of claim 1 or 2 as well as by a manufacturing method for a blading with the features of claim 12. Advantageous enhancements are the subject of the dependent claims.
According to a first aspect of the present invention, in the case of a blading for a turbomachine, in particular a compressor stage or turbine stage of an internal combustion engine, preferably a gas turbine, in which thickened areas and depressions are formed on a lateral wall having a plurality of blades, for each blade of the plurality of blades, at least one depression is disposed at a pressure side of the blade and at least one thickened area is disposed at a suction side of the blade.
According to a second aspect of the present invention, in the case of a blading for a turbomachine, in particular a compressor stage or turbine stage of an internal combustion engine, preferably a gas turbine, in which thickened areas and depressions are formed on a lateral wall having a plurality of blades, for each blade of the plurality of blades, at least one depression is disposed at a suction side of the blade and at least one thickened area is disposed at a pressure side of the blade.
By this targeted combined introduction of thickened areas and depressions at pressure or suction sides, respectively, an advantageous local adaptation of the static pressure and the flow velocity can be achieved, whereby secondary flows can be influenced advantageously and flow losses can be reduced. In addition to the reduction in losses in the blade channels over a large operating range of turbomachines, another advantage of this configuration also may lie in an enlarging of the operating range of turbomachines. An advantage may also lie in a simple structural conversion and/or applicability for already existing designs of turbomachines.
As blading in the sense of the present invention, an arrangement of rotating blades and/or an arrangement of guide vanes, in particular of one or more stages, is particularly intended. A blading according to the invention is particularly suitable for high-pressure compressors. In a preferred embodiment, an aircraft engine has a blading according to the invention.
A lateral wall in the sense of the present invention can be on the hub or rotor side, and/or the housing side and can be fixed on the hub or rotor, and/or the housing. Thus, a lateral wall may comprise the hub-side, i.e., radially inner and hub-fixed peripheral face of a rotating-blade grid, and/or the housing-side, i.e., radially outer peripheral face of a rotating-blade grid, which can be formed, in particular, by a shroud fixed to the hub or by an inner face fixed to the housing. Likewise, a lateral wall may comprise the housing-side, radially outer peripheral face and/or the hub-side peripheral face of a guide-vane grid, which can be formed, in particular, by a shroud fixed on the housing or by an outer face fixed on the hub.
In the sense of the present invention, a depression is to be understood particularly to be a region of the lateral wall that is offset radially inwardly relative to other regions of the lateral wall, while a thickened area or elevation in the sense of the present invention is to be understood particularly to be a region of the lateral wall that is offset radially outwardly relative to other regions of the lateral wall. A depression or thickened area in the sense of the present invention may be recessed or extended radially inwardly or outwardly, respectively, in particular, in relation to a particularly straight or curved reference conical surface that lies concentrically to an axis of rotation. The reference conical surface, in particular, can run through the radially innermost or radially outermost points of the lateral wall or therebetween. In particular, a radius of the reference conical surface may correspond to the average of the maximum and minimum or all radial extensions of the lateral wall. In addition, the depression or thickened area may also relate to a reference conical surface that runs through a non-contoured region of the lateral wall or a root or a tip of the blades.
In the sense of the present invention, a thickened area can be understood, in particular, as a radial dimension that is larger in comparison to the depression, while a depression is understood correspondingly as a radial dimension that is smaller in comparison to the thickened area.
For example, if one considers a sinusoidally channeled lateral wall in the peripheral direction, then the mountains or valleys represent thickened areas or depressions, respectively, relative to the central line, in the sense of the present invention. Likewise, one can proceed from a reference conical surface through the radially maximum or minimum amplitudes of the sinusoidally channeled lateral wall. Here also, the valleys represent depressions and the mountains represent thickened areas relative to this reference conical surface, since they lie in contrast radially further in (or further out).
A depression (thickened area) disposed at a suction or pressure side of the blade can be particularly characterized in that in a section in the peripheral direction, which is perpendicular to an axis of rotation of the turbomachine (see, e.g., L4 to L8 in EP 1 995 410 A1), in particular such a section in the axial center of the blading (see, e.g., L6 in EP 1 995 410 A1), the lateral wall at the blade root is sunk radially inwardly (elevated radially outwardly).
The lateral wall is preferably not contoured in the axial direction in front of and/or behind the pressure-side depressions and/or suction-side thickened areas, i.e., it has the same radius over the entire circumference of a radial section.
In a preferred embodiment, the depression or thickened area disposed at the pressure side of the blade and/or the thickened area or depression disposed at the suction side of the blade, viewed in the direction of flow, begins in front of, at, or in back of the leading edge of the blade.
The depression or thickened area disposed at the blade's pressure side and/or the thickened area or depression disposed in the region of the blade's suction side in the axial direction preferably extends over at least 10%, preferably at least 30%, in particular at least 50% and most preferred 60% of the axial grid length, and/or 100% at most, particularly 80% at most of the axial grid length, in each case measured between the leading and trailing edges of the blade.
In a preferred embodiment for the blading, the thickened area or depression disposed at the blade's suction side and/or the depression or thickened area disposed at the blade's pressure side is (are) disposed completely or partially in the axial half of the blade grid facing the inlet side.
In a preferred embodiment, a radial extreme point of the depressions and/or thickened area that is (are) disposed at a pressure or suction side of the blade in the axial direction is distanced at least 10%, in particular at least 20%, preferably at least 40% and/or 90% at most, in particular 80% at most, preferably 60% at most, of the blade chord length from the leading edge of the blade. In particular, a radial minimum of the depressions can lie in a region that extends between 20% and 60% of the blade chord length, measured from the leading edge of the blade. In particular, a radial maximum of the thickened area can lie particularly in a region that extends between 40% and 80% of the blade chord length, measured from the leading edge of the blade
Another thickened area is preferably disposed in each case for the blading in the half facing the outlet side. This additional thickened area can be disposed and configured peripherally symmetrical. Alternatively, this additional thickened area can be disposed and configured peripherally asymmetrical. In a preferred embodiment, the ratio of the extent of this additional thickened area in the peripheral direction to its extent in the axial direction or the direction of flow can be smaller than 1, i.e., this additional thickened area can be “stretched” in the axial direction or the direction of flow.
The additional thickened area disposed in the half facing the outlet edge can extend preferably in the peripheral direction, at least essentially, from one blade to the adjacent blade. In the axial direction, the second thickened area can extend over at least 10% of the axial grid length in a preferred embodiment. This additional thickened area can be radially higher or lower than the thickened area disposed at a suction or pressure side of the blade.
Likewise, the depression disposed at a suction or pressure side of the blade can extend on both sides of this additional thickened area, i.e., this additional thickened area can be disposed in the depression disposed at a suction or pressure side of the blade. Such an additional thickened area then divides a fluid flow in the depression disposed at a suction or pressure side of the blade.
Additionally or alternatively, in a preferred embodiment, a peripherally symmetrical or peripherally asymmetrical additional thickened area can be disposed at the leading edge of a blade, in particular upstream of a depression disposed at a suction or pressure side of the blade in the direction of through flow. In this way, a fluid flow can be conducted away from the blade root into the depression disposed at a suction or pressure side of the blade.
The present invention can preferably be applied in blade grids that have a bent, particularly at least substantially orthogonal, transition from the blade's pressure side and/or suction side to the lateral wall; likewise also in the case of blade grids that have a rounded root surface in the transition region from the blade's pressure side and/or suction side to the lateral wall.
According to another aspect of the present invention relating to the manufacturing method, in the case of a manufacturing method for a blading for a turbomachine, at least one original shaping, reshaping and/or cutting treatment is executed in such a way that in the case of a lateral wall having a plurality of blades, thickened areas and depressions are formed, at least one depression or thickened area being formed at a blade's pressure side and at least one thickened area or depression being formed at a blade's suction side for each blade of the plurality of blades.
Advantageously, a blading having a high efficiency, particularly in a rapidly rotating high-pressure compressor (stage) can be provided by the configuration according to the invention.